Numerous companies manufacture devices which enable medicines to be injected into a patient directly into the bloodstream and enable samples of blood to be taken from the patient. Other similar devices and catheters may be inserted for long-term dialysis or intravenous feeding. These devices are sometimes termed port-a-caths, infusa-ports, and venous access devices. Two manufacturers of these devices are C. R. Bard, Inc. and AngioDynamics. These devices often consist of a port, which also may be referred to as a drum, and a catheter which is coupled to the port. The catheter is typically inserted into a major vein, leading to a central vein, in the patient. Thus, the medicine is injected with a syringe, using a special needle, through the patient's skin directly into the port and carried directly into the patient's bloodstream through the catheter. Dialysis and feeding catheters are not usually coupled to a port, but come out through the skin. The section of the catheter outside the skin has a closure mechanism to keep the catheter shut and sterile when not in use. Just within the skin, a dialysis catheter has a Dacron cuff which anchors the catheter to the tissues and acts as a bacteriostatic bacterial barrier. All of these devices are usually intended to be implanted into the patient for long periods of time, e.g. months or even years. During this time, tissue may build up along the catheter and adhere to the catheter, both inside the vessel, along the tract, and outside the vessel, so that it may not be possible to remove the catheter without damaging the blood vessel causing serious, life-threatening bleeding. Accordingly, removing catheters that have been implanted for a long time may be problematic, and the present common practice, as advised by the manufacturer of these devices, is to leave the catheter in place indefinitely.